title: Platelet-rich plasma: quantitative assessment of growth factor levels and comparative analysis of activated and inactivated groups.
abstract: BACKGROUND
  Platelet-rich plasma (PRP) has more concentrated platelets than normal plasma (approximately 150-400×10(3) cell/dL). Platelets excrete several growth factors and cytokines that are associated with the healing and regeneration process. However, even though PRP is widely used, the mechanism or actual effect is presently unclear. Therefore, this study was performed to investigate the levels of growth factors and platelet concentration rate.
  
  
  METHODS
  Autologous blood for preparing PRP was obtained from healthy subjects aged 25 to 35 years. The samples were divided into 4 experimental groups (inactivated whole blood, inactivated PRP, activated whole blood with thrombin and calcium chloride, and activated PRP). The platelet counts in the blood were analyzed and the growth factors were quantitatively measured. A statistical analysis was performed by using Dunn's multiple comparison test.
  
  
  RESULTS
  In the blood cell analysis, the platelet count of the PRP group was approximately 4.25 times higher than that of the whole blood group. In the quantitative analysis of growth factors, the platelet-derived growth factor (PDGF)-AB, PDGF-BB, and transforming growth factor-β of the inactivated and activated PRP groups were higher than those of the inactivated and activated whole blood groups (P<0.05).
  
  
  CONCLUSIONS
  In this study, the platelet count and the levels of PDGF-AB and PDGF-BB in the PRP were determined. Further, more research is required on the bioactivity level of the growth factors secreted during the process of PRP preparation and the potency of growth factors that can be exerted physiologically in vivo.
authors.affiliation: Department of Plastic and Reconstructive Surgery, Kyungpook National University School of Medicine, Daegu, Korea.
authors.forename: Jeong Woo
authors.initials: JW
authors.lastname: Lee
authors.forename: O Hyun
authors.initials: OH
authors.lastname: Kwon
authors.forename: Taek Kyun
authors.initials: TK
authors.lastname: Kim
authors.forename: Young Kyoo
authors.initials: YK
authors.lastname: Cho
authors.forename: Kang Young
authors.initials: KY
authors.lastname: Choi
authors.forename: Ho Yun
authors.initials: HY
authors.lastname: Chung
authors.forename: Byung Chae
authors.initials: BC
authors.lastname: Cho
authors.forename: Jung Dug
authors.initials: JD
authors.lastname: Yang
authors.forename: Jun Ho
authors.initials: JH
authors.lastname: Shin
keywords: Platelet count; Platelet-derived growth factor; Platelet-rich plasma; Transforming growth factors